The epoxidation of alkene into alkylene oxide by reacting the alkene with an organic hydroperoxide is known in the art.
For instance, in the commonly known method for co-producing propylene oxide and styrene starting from ethylbenzene, the aforementioned epoxidation reaction is applied. In general this co-production process involves the steps of (i) reacting ethylbenzene with oxygen or air to form ethylbenzene hydroperoxide, (ii) reacting the ethylbenzene hydroperoxide thus obtained with propene in the presence of an epoxidation catalyst to yield propylene oxide and 1-phenyl-ethanol, and (iii) converting the 1-phenyl-ethanol into styrene by dehydration using a suitable dehydration catalyst.
Another method for producing alkylene oxide is the coproduction of propylene oxide and methyl tert.-butyl ether (MTBE) starting from isobutane and propene. This process is well known in the art and involves similar reaction steps as the styrene/propylene oxide production process described in the previous paragraph. In the epoxidation step tert-butyl hydroperoxide is reacted with propene forming propylene oxide and tert-butanol in the presence of a heterogeneous epoxidation catalyst. Tert-butanol is subsequently etherified with methanol into MTBE, which is used as an additive in motor fuels.
U.S. Pat. No. 5,849,937 relates to an olefin epoxidation process using a plurality of reactor vessels each containing a fixed bed of a heterogeneous catalyst. When the activity of the catalyst in an individual reactor vessel falls to an undesirably low level, said reactor vessel is taken out of service and a replacement reactor vessel containing fresh or regenerated catalyst is introduced. The temperature of the feedstream is controlled such that the temperature does not exceed 125° C. In Comparative Example 1, the temperature of the feed to the reactor vessel is about 38° C. at the start of the epoxidation cycle and the heat-exchangers are initially by-passed. The temperature is gradually increased as necessary to maintain the desired level of conversion. At the end of the epoxidation cycle, the feed inlet temperature of the heat exchanger (and therefore the reactor outlet temperature) is 121° C. for each reactor.
As mentioned in U.S. Pat. No. 5,849,937, during operation the temperature of a bank of epoxidation reactors generally is increased in time to maintain the desired level of conversion which would otherwise decrease due to catalyst deactivation.